Video/interview: 'Inside Llewyn Davis' star Oscar Isaac

Asked to choose if great songwriting or great performance ability is more important for a musician, "Inside Llewyn Davis" star Oscar Isaac hesitates, wavers, then decides.

"I'd say definitely songwriting. Because if you perform a [bleepy] song, then just `cause you're really good at performing it ..." says the 33-year-old actor, who plays the film's titular folk singer, at the James Hotel. "You can put diamonds on a turd, I guess."

In other words, you can try, but you can't fake quality. That's never been an issue for the Coen brothers ("No Country for Old Men," "Fargo"), who bring their traditional warped sense of humor and uncompromising view of the world's challenges to "Llewyn Davis," opening Friday. In his first leading role, Isaac ("Drive," "Robin Hood") is terrific as a struggling musician in 1961 New York who's more familiar with sleeping on couches than earning significant money for his versions of classic songs. Early folk singers played standards because that was the way songs were passed down before recorded music became the norm, Isaac notes.

Isaac, who chalks up his quick onscreen success to the sort of luck Llewyn doesn't have, has played in bands for much of his life. So this wasn't a case of an actor having to pick up an instrument and learn to perform for the first time. The potential Oscar nominee says the New York club shows he played to prepare for the film allowed him to simply "face an audience just with a guitar." No one recognized him from his films. No one booed. Some asked where they could buy his albums.

He's not the only actor-musician bridging the artistic forms, of course. Justin Timberlake co-stars in the film as Jim, the on- and offstage partner of the pregnant woman (Carey Mulligan, Isaac's "Drive" co-star) who isn't sure if Jim or Llewyn is the father. Yes, the "tricky" subject of mixing music and movies came up in conversation between Isaac and Timberlake.

"You don't want to be looked at as just an opportunist," Isaac says. "But if you actually have a true desire and you feel like you can contribute something to the medium, then I think it's fair to try ... I feel confident in that I have something to offer in both the music and film [industries], and I think [Justin] probably feels the same way."

Isaac has nothing to worry about. The film contains excellent performances and excellent music, curated by the Coens and T-Bone Burnett ("Crazy Heart") and assisted by Mumford and Sons frontman (and Mulligan's husband) Marcus Mumford. It provided Isaac the rare opportunity to jam with Timberlake, Mumford and bluegrass outfit the Punch Brothers -- including playing the entirety of Radiohead's "In Rainbows."

"We're all young guys that grew up listening to Radiohead," he says. "So the fact that we're into traditional music but still can dig into our favorites, that was an incredible night."

Incredible on a different level: To film some of Llewyn's many scenes trying to control a housecat, Isaac, who as a kid thought he could communicate with cats by meowing, had to be connected to the feline actors with a wire. I note that this is an experience most people don't have.

"And really they shouldn't," he says, not missing a beat. "I don't recommend it. A cat generally doesn't want to be attached to you by a wire, so it will try to become unattached by whatever means necessary."

Is there an animal he'd recommend attaching via wire instead?

"A dead one maybe."

Plus:On a moment during preparation or filming when he wanted to be a better musician: "That's always the challenge. Never being satisfied. I think that's good. Obviously if you take it too far it becomes perfectionism and it can turn into neuroses, but I think that feeling of, `I feel like it could be better; what work can I do that can make it be deeper and truer?,' that's the constant search for an artist I think."If he had to choose between the Coens' "Raising Arizona" or "The Big Lebowski": "I'd probably go with `Raising Arizona' just because it's the first one that I saw. And I was like, `What is this weird tone?' It's so funny, yet I feel so weird and sad after it's over. `Lebowski's' a close second.""Fargo" or "No Country For Old Men"? "Um, I don't know man. I can't really pick between those. It's too hard."A song he likes on the radio now: "I really like that `Why I Love You,' the Kanye and Jay-Z song. (sings) `I love you so ... duh nuh nuh nuh ... I love you so ...' That song's awesome."

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